Neuro-Ophthalmology Practice Questions

Q: Which of the following drugs does NOT cause retinal changes?

Amiodarone. **Explanation:** The correct answer is **Amiodarone**. In neuro-ophthalmology and ocular pharmacology, it is crucial to distinguish between drugs that affect the **retina** and those that affect the **cornea or optic nerve**. **1. Why Amiodarone is the correct answer:** Amiodarone is classically associated with **Vortex Keratopathy (Cornea Verticillata)**—fine, whorl-like golden-brown deposits in the basal epithelium of the **cornea**. While it can rarely cause optic neuropathy, it does **not** typically cause retinal pigmentary changes or retinal toxicity. **2. Analysis of Incorrect Options (Drugs causing Retinal changes):** * **Tamoxifen:** Used in breast cancer treatment, it causes **Tamoxifen Retinopathy**, characterized by bilateral, fine, yellow, crystalline deposits in the macula (paramacular area) and cystoid macular edema. * **Hydroxychloroquine (HCQ):** A high-yield topic. It causes **"Bull’s Eye Maculopathy"** due to the drug binding to melanin in the Retinal Pigment Epithelium (RPE). Screening with 10-2 Visual Fields and SD-OCT is mandatory for long-term users. * **Vigabatrin:** An antiepileptic drug known for causing **permanent peripheral visual field constriction** due to localized retinal toxicity (specifically affecting the photoreceptors and ganglion cells). **Clinical Pearls for NEET-PG:** * **Cornea Verticillata Mnemonic:** "**C**hloroquine, **A**miodarone, **I**ndomethacin, **T**amoxifen" (**CAIT**) and **Fabry’s disease**. * **Bull’s Eye Maculopathy Differential:** HCQ toxicity, Stargardt’s disease, Cone-Rod dystrophy, and Benign Concentric Macular Dystrophy. * **Thioridazine & Chlorpromazine:** Other psychiatric drugs that cause pigmentary retinopathy (salt and pepper appearance).

Q: Internuclear ophthalmoplegia is caused due to a lesion in which of the following?

Medial longitudinal fasciculus. **Explanation:** **Internuclear Ophthalmoplegia (INO)** is a classic neuro-ophthalmological syndrome characterized by an impairment of horizontal conjugate gaze. **1. Why Medial Longitudinal Fasciculus (MLF) is correct:** The MLF is a heavily myelinated nerve tract that connects the **Abducens nucleus (CN VI)** on one side of the pons to the **contralateral Oculomotor nucleus (CN III)** in the midbrain. For horizontal gaze, the Abducens nucleus triggers the lateral rectus (abduction) and simultaneously sends a signal through the MLF to the opposite Medial Rectus subnucleus to trigger adduction. A lesion in the MLF disrupts this communication, leading to: * **Ipsilateral failure of adduction** (the eye on the side of the lesion cannot move inward). * **Contralateral abducting nystagmus** (a compensatory mechanism in the healthy eye). **2. Why other options are incorrect:** * **Occipital lobes:** Responsible for visual processing and perception, not the coordination of extraocular muscle nuclei. * **Pretectal fibers:** Involved in the pupillary light reflex pathway (e.g., Parinaud syndrome). * **Para pontine reticular formation (PPRF):** This is the "horizontal gaze center." A lesion here causes **horizontal gaze palsy** (neither eye can look toward the side of the lesion), unlike INO where abduction is preserved. **Clinical Pearls for NEET-PG:** * **Etiology:** In young adults, the most common cause is **Multiple Sclerosis** (often bilateral). In elderly patients, it is usually a **Vascular stroke** (often unilateral). * **Convergence:** In a posterior MLF lesion, convergence is typically **preserved** because the pathway for convergence bypasses the MLF. * **One-and-a-half Syndrome:** Caused by a combined lesion of the PPRF (or Abducens nucleus) and the MLF on the same side.

Q: Anisocoria in dim light is maximally seen in which condition?

Horner syndrome. **Explanation:** The key to solving anisocoria questions lies in determining whether the difference in pupil size increases in **dim light** or **bright light**. **1. Why Horner Syndrome is correct:** Anisocoria that is **more pronounced in dim light** indicates a failure of the pupil to dilate (a **sympathetic** defect). In Horner syndrome, there is a lesion in the oculosympathetic pathway, leading to miosis (constricted pupil) on the affected side. In dim light, the normal pupil dilates fully, while the Horner pupil fails to dilate, making the discrepancy between the two eyes maximal. This is often associated with a "dilation lag." **2. Why the other options are incorrect:** * **3rd Nerve Palsy & Parasympathetic Paralysis:** These involve the parasympathetic fibers responsible for constriction. Therefore, the affected pupil is abnormally large (mydriasis). The anisocoria becomes **more pronounced in bright light**, as the normal pupil constricts while the affected pupil remains dilated. * **Pharmacological Mydriasis:** This is caused by drugs (like Atropine) that block the sphincter pupillae. Similar to 3rd nerve palsy, the anisocoria is **maximal in bright light** because the medicated pupil cannot constrict. **Clinical Pearls for NEET-PG:** * **The Rule of Light:** * Anisocoria ↑ in **Dim** light = **Sympathetic** problem (e.g., Horner’s). * Anisocoria ↑ in **Bright** light = **Parasympathetic** problem (e.g., Adie’s Tonic Pupil, 3rd Nerve Palsy). * **Horner’s Triad:** Miosis, partial Ptosis (Muller’s muscle), and Anhidrosis. * **Cocaine Test:** In Horner’s, the pupil will **not** dilate after cocaine drops (confirms diagnosis). * **Apraclonidine Test:** Causes "reversal of anisocoria" (dilation) in Horner’s due to denervation supersensitivity.

Q: Diagnose the ocular pathology.

Papilledema. ***Papilledema*** - Characterized by **optic disc swelling** with **blurred disc margins**, **flame-shaped hemorrhages**, and **cotton wool spots** around the optic nerve head. - Associated with **elevated intracranial pressure** causing bilateral optic disc edema with preserved **central vision** initially. *Primary optic atrophy* - Shows a **pale optic disc** with **sharp, well-defined margins** and **loss of nerve fiber layer**. - Results from **chronic optic nerve damage** with **reduced visual acuity** and **visual field defects**. *Primary open angle glaucoma* - Presents with **increased cup-to-disc ratio** (>0.5) and **vertical cupping** of the optic disc. - Characterized by **rim thinning** and **nerve fiber layer defects** without disc swelling or hemorrhages. *Central retinal artery occlusion* - Shows **cherry-red spot** at the macula with **pale, whitish retina** due to retinal ischemia. - Fundoscopy reveals **attenuated arterioles** and **absence of arterial blood flow** with sudden severe vision loss.

Q: Opsoclonus is a feature of which of the following conditions?

Carcinoma of the lung. **Explanation:** **Opsoclonus** is a rare, high-frequency, involuntary, multivectorial eye movement disorder characterized by spontaneous, rapid, and chaotic "dancing eyes." It is often associated with myoclonus (Opsoclonus-Myoclonus-Ataxia Syndrome). **1. Why Carcinoma of the Lung is Correct:** In adults, opsoclonus is most commonly a **paraneoplastic manifestation**. It is frequently associated with **Small Cell Lung Carcinoma (SCLC)**, mediated by the **anti-Ri (ANNA-2)** antibody. The underlying mechanism involves an immune-mediated attack on the brainstem and cerebellum triggered by the underlying malignancy. **2. Analysis of Incorrect Options:** * **Retinoblastoma:** While a common pediatric ocular tumor, it does not cause opsoclonus. However, in children, opsoclonus is a classic paraneoplastic sign of **Neuroblastoma** (not Retinoblastoma). * **Focal seizure with dyscognitive changes:** Seizures typically present with rhythmic nystagmoid movements or tonic-clonic deviations, not the chaotic, non-rhythmic movements of opsoclonus. * **Wilson’s Disease:** Extrapyramidal damage in Wilson’s disease typically manifests as a "wing-beating" tremor, dystonia, or parkinsonism. Ocular findings include the **Kayser-Fleischer (KF) ring** and "sunflower cataracts," but not opsoclonus. **High-Yield Clinical Pearls for NEET-PG:** * **Pediatric Association:** Always rule out **Neuroblastoma** in a child presenting with "Dancing Eyes, Dancing Feet" (Opsoclonus-Myoclonus Syndrome). * **Adult Association:** Small Cell Lung Cancer (SCLC) and Breast Cancer. * **Anatomical Site:** Dysfunction is localized to the **omnipause neurons** in the nucleus raphe interpositus of the pons, which normally inhibit saccadic bursts. * **Key Antibody:** **Anti-Ri** is the most high-yield antibody associated with paraneoplastic opsoclonus.

Q: Which of the following is NOT a feature of Horner syndrome?

Exophthalmos. **Explanation:** Horner syndrome results from a lesion in the **oculosympathetic pathway**. The sympathetic nervous system is responsible for pupillary dilation, eyelid elevation, and vasoconstriction. When this pathway is interrupted, a classic triad of symptoms occurs. **Why Exophthalmos is the correct answer:** Horner syndrome actually causes **Enophthalmos** (the appearance of a sunken eye), not exophthalmos. This is a "pseudo-enophthalmos" caused by the narrowing of the palpebral fissure due to the drooping of the upper lid and slight elevation of the lower lid. Exophthalmos (protrusion of the eyeball) is typically associated with conditions like Graves' ophthalmopathy or orbital tumors. **Why the other options are incorrect:** * **Ptosis:** Occurs due to paralysis of **Müller’s muscle** (superior tarsal muscle), which is sympathetically innervated. This is a "partial ptosis" (1-2mm) compared to the complete ptosis seen in 3rd nerve palsy. * **Miosis:** The loss of sympathetic supply to the **dilator pupillae** muscle leads to an unopposed action of the sphincter pupillae (parasympathetic), resulting in a constricted pupil. * **Conjunctival Congestion:** Sympathetic nerves normally maintain vasoconstriction. Their loss leads to **vasodilation** of the conjunctival and facial blood vessels, causing redness and flushing. **High-Yield Clinical Pearls for NEET-PG:** 1. **The Triad:** Ptosis, Miosis, and Anhidrosis (loss of sweating). 2. **Inverse Ptosis:** Elevation of the lower eyelid (due to paralysis of the inferior tarsal muscle). 3. **Cocaine Test:** In Horner syndrome, the pupil **fails to dilate** after cocaine drops. 4. **Apraclonidine Test:** Causes **reversal of anisocoria** (the Horner pupil dilates while the normal pupil remains unchanged). 5. **Heterochromia Iridum:** Seen specifically in **congenital** Horner syndrome (the affected eye is lighter).

Question 1

A 40-year-old female presented with an excruciating headache, ptosis, downward and outward gaze of the eyeball, and a large pupil. She also complained of blurred and double vision. An magnetic resonance angiogram scan showed an aneurysm of the circle of Willis. Which artery gives rise to the offending aneurysm?

Accepted Answer

Posterior communicating artery

Answer

Anterior choroidal artery

Answer

Anterior communicating artery

Answer

Charcot-Bouchard's artery

Question 2

Which of the following drugs does NOT cause retinal changes?

Accepted Answer

Amiodarone

Answer

Tamoxifen

Answer

Hydroxychloroquine

Answer

Vigabatrin

Question 3

Internuclear ophthalmoplegia is caused due to a lesion in which of the following?

Accepted Answer

Medial longitudinal fasciculus

Answer

Occipital lobes

Answer

Pretectal fibres

Answer

Para pontine reticular fibres

Question 4

Papilledema is caused by tumors arising from all the following structures except:

Accepted Answer

Medulla

Answer

Cerebrum

Answer

Cerebellum

Answer

Thalamus

Question 5

Anisocoria in dim light is maximally seen in which condition?

Accepted Answer

Horner syndrome

Answer

3rd nerve palsy

Answer

Pharmacological mydriasis

Answer

Parasympathetic paralysis

Question 6

All of the following findings are associated with optic neuritis except?

Accepted Answer

Metamorphopsia

Answer

Painful ocular movements

Answer

Defective color perception

Answer

Defective depth perception

Question 7

A 23-year-old woman complains of progressive loss of vision and papilledema. Investigations show normal findings on CT scan. A lumbar puncture shows marked elevation of pressure. What is the most likely diagnosis?

Accepted Answer

Pseudotumor cerebri

Answer

Corpus cavernous thrombosis

Answer

Cavernous sinus thrombosis

Answer

Retinoblastoma

Question 8

Diagnose the ocular pathology.

Accepted Answer

Papilledema

Answer

Primary optic atrophy

Answer

Primary open angle glaucoma

Answer

Central retinal artery occlusion

Question 9

Opsoclonus is a feature of which of the following conditions?

Accepted Answer

Carcinoma of the lung

Answer

Retinoblastoma

Answer

Focal seizure with dyscognitive changes

Answer

Extrapyramidal damage in Wilson's disease

Question 10

Which of the following is NOT a feature of Horner syndrome?

Accepted Answer

Exophthalmos

Answer

Ptosis of the upper eyelid

Answer

Miosis

Answer

Conjunctival congestion

Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology — MCQs

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